Micro Vein Enhancer

ABSTRACT

The present invention is a Miniature Vein Enhancer that includes a Miniature Projection Head. The Miniature Projection Head may be operated in one of three modes, AFM, DBM, and RTM. The Miniature Projection Head of the present invention projects an image of the veins of a patient, which aids the practitioner in pinpointing a vein for an intravenous drip, blood test, and the like. The Miniature projection head may have a cavity for a power source or it may have a power source located in a body portion of the Miniature Vein Enhancer. The Miniature Vein Enhancer may be attached to one of several improved needle protectors, or the Miniature Vein Enhancer may be attached to a body similar to a flashlight for hand held use. The Miniature Vein Enhancer of the present invention may also be attached to a magnifying glass, a flat panel display, and the like.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/249,462, filed on Apr. 10, 2014, which is a continuation of Ser. No.13/444,940, filed on Apr. 12, 2012, now issued as U.S. Pat. No.8,750,970, which is a continuation of U.S. application Ser. No.11/985,343, filed on Nov. 14, 2007, now issued as U.S. Pat. No.8,255,040, which is a continuation in part of both: U.S. applicationSer. No. 11/700,729, filed on Jan. 31, 2007, now issued as U.S. Pat. No.8,838,210, which claims priority on U.S. Provisional Patent ApplicationSer. No. 60/817,623, filed Jun. 29, 2009; and also U.S. application Ser.No. 11/478,322, filed on Jun. 29, 2006, now issued as U.S. Pat. No.8,478,386, which claims priority on U.S. Provisional Application Ser.No. 60/757,704, filed on Jan. 10, 2006, all disclosures of which areincorporated herein by reference.

FIELD OF INVENTION

The invention described herein relates generally to an imaging device,in particular, an imaging means for enhancing visualization of veins,arteries and other subcutaneous structures of the body for facilitatingfluid insertion into or extraction from the body or otherwisevisualizing subcutaneous structures for diagnosis of the medicalcondition of a patient or administration of medical treatment to apatient.

BACKGROUND OF THE INVENTION

A visit to a doctor's office, a clinic or a hospital may necessitatevascular access that is, the insertion of a needle or catheter into apatient's vein or artery. These procedures may be required for thefollowing reasons: to administer fluids, drugs or solutions, to obtainand monitor vital signs, to place long-term access devices, and toperform simple venipunctures. Vascular access ranks as the most commonlyperformed invasive, medical procedure in the U.S—over 1.4 billionprocedures annually—as well as the top patient complaint among clinicalprocedures. The overwhelming majority of vascular access procedures isperformed without the aid of any visualization device and relies on whatis observed through the patient's skin and by the clinician's ability tofeel the vessel. Medical literature reports the following statistics:28% first attempt TV failure rate in normal adults, 44% first attempt IVfailure in pediatrics, 43% of pediatric IVs require three or moreinsertion attempts, 23% to 28% incidence of extravasations/infiltration,12% outright failure rate in cancer patients, 25% of hospitalin-patients beyond three days encounter difficult access.

It is known in the art to use an apparatus to enhance the visualappearance of the veins in a patient to facilitate insertion of needlesinto the veins. An example of such a system is described in U.S. Pat.Nos. 5,969,754 and 6,556,858 incorporated herein by reference as well asa publication entitled “The Clinical Evaluation of Vein ContrastEnhancement”. Luminetx is currently marketing such a device under thename “Veinviewer Tm aging System” and information related thereto isavailable on its website, which is incorporated herein by reference.

The Luminetx Vein Contrast Enhancer (hereinafter referred to as LVCE)utilizes an infrared light source for flooding the region to be enhancedwith infrared light generated by an array of LEDs. A CCD imager is thenused to capture an image of the infrared light reflected off thepatient. The resulting captured image is then projected by a visiblelight projector onto the patient in a position closely aligned with theimage capture system. Given that the CCD imager and the image projectorare both two dimensional, and do not occupy the same point in space, itis relatively difficult to design and build a system that closely alignsthe captured image and the projected image.

A further characteristic of the LVCE is that both the imaging CCD andthe projector have fixed focal lengths. Accordingly, the patient must beat a relatively fixed distance relative to the LVCE. This necessitatesthat the LVCE be positioned at a fixed distance from the region of thepatient to be enhanced.

The combination of the size of the LVCE and the fixed focal arrangementprecludes using the LVCE as small portable units that are hand held:

Other patents such as U.S. Pat. No. 6,230,046, issued to Crane et al.assigned to The United States of America as represented by the Secretaryof the Air Force, implement a light source for illuminating ortransilluminating the corresponding portion of the body with light ofselected wavelengths and a low-level light detector such as an imageintensifier tube (including night vision goggles), a photomultipliertube, photodiode or charge coupled device, for generating an image ofthe illuminated body portion, and optical filter(s) of selected spectraltransmittance which can be located at the light source(s), detector, orboth.

All citied references are incorporated herein by reference in theirentireties. Citation of any reference is not an admission regarding anydetermination as to its availability as prior art to the claimedinvention.

SUMMARY OF INVENTION

Finding a vein, necessary for administering intravenous solutions, dripsand the like, can often be difficult. During venous penetration, whetherfor an injection or drip, it is essential to stick a vein in exactly theright location. If a practitioner is only slightly off center, theneedle will more then likely just roll off.

The present invention is a Miniature Vein Enhancer that includes aMiniature Projection Head. The Miniature Projection Head of the presentinvention implements a polarized laser light. This diminishes theeffects of specular reflection off the surface of the skin. TheVeinviewer Imaging System, produced by Luminetx, uses a polarized filterto polarize the LED light. This polarized LED light is then rotated 90°in front of the camera, thus causing increased power loss.

In addition, the IR and visible lasers in the present invention can bemodulated to allow a regular photodiode to detect the different signalsfrom each wavelength separately. Furthermore, the IR laser power of thepresent invention is dynamically altered during each scan line, thusincreasing the working range of the photodiode, and allowing forconstant DC gain.

One key feature of the present invention, not present in the prior art,is the use of a hot mirror. A brief description now follows. First, ahot mirror is a specialized dielectric mirror, a dichromaticinterference filter often employed to protect optical systems byreflecting heat back into the light source. In addition, hot mirrors canbe designed to be inserted into at optical system at an incidence anglevarying between zero and 45 degrees. Hot mirrors are useful in a varietyof applications where heat build-up can damage components or adverselyaffect spectral characteristics of the illumination source. Thesecharacteristics, although useful in some applications, are notparticularly important within the context of the present invention.Generally, wavelengths reflected by an infrared hot mirror range fromabout 750 to 1250 nanometers. By transmitting visible light wavelengthswhile reflecting infrared, hot mirrors can also serve as dichromaticbeam splitters for specialized applications in fluorescence microscopy,as in the present invention. As mentioned above, hot mirrors are mirrorsthat may be coated with a Dichroic material, or the like. A Dichroicmaterial is either one which causes visible light to be split up intodistinct beams of different wavelengths, or one which light rays havingdifferent polarizations are absorbed by different amounts, the former isimplemented in the present invention.

The present invention also improves on the Crane Patent. In Crane, thevein enhancer implements two separate devices, one for illuminationand/or transillumination and a separate device used for detecting thelow light. Such a configuration is awkward . and difficult to operate.In addition, having two separate devices increases the likelihood losingone of them.

The present invention can implement multiple photo detectors spatiallyseparated so as to increase sensitivity, reduce speckle, and reducespecular reflection. However, as mentioned previously, one can achieve areasonable result by using a single PD, this will depend on the desiredoutput and/or operating needs.

The scanning method implemented with the present invention is unique. Ingeneral, the lower level of precision required, the easier it is toproduce the pattern. In the present invention (the embodiment withoutimage memory), as opposed to a traditional laser projectors known in theart, there is no need for a reproducible scan pattern, that is, fromframe to frame the laser scan lines do not need to fall reproduciblyupon the scan lines of the prior frame, thus, there is no need to knowthe instantaneous position of the laser. The reason being, the visiblelight of the present invention is coaxially aligned to the 740 un laser.The visible light is a function of the received image in real time.Accordingly, whatever location is being imaged is instantaneously beingprojected.

The present invention also implements a scanner. The scanner of thepresent invention can include an amplitude modulated circular mirror. Inthis case a mirror is arranged to run at resonance in a circular or ovalpattern. The magnitude of the circle is then amplitude modulated at arate in excess of 30 Hz (to avoid appearance of flicker). Accordingly, ascan pattern is formed which starts with small concentric circles andgrows sequentially larger, until reaching a limit and than collapsingsequentially to the smallest circle. Some advantages of thisconfiguration include: circle and oval scan; mirror and laser spotalways moving, hence, no down time; center of image naturally brighter;scan lines per inch can be denser in center; calibration line is outsidecircle (can be clipped by housing); and operation at resonance means lowpower.

The miniature vein enhancer of the present invention may be used by apractitioner to locate a vein, particularly useful when trying to locatea vein in the very old or very young. More then fifty percent ofattempts to find a vein, in old people, who have a generally highpercentage of loose, fatty tissue, and children, who have a generallyhigh percentage of small veins and “puppy fat”, are unsuccessful. Thepresent invention is aimed at reducing and/or preventing the discomfortand delay associated with botched attempts to pierce veins forinjections and blood tests. In addition, the present invention can cutthe time it takes to set up potentially life-saving intravenous drip.

OBJECTS OF THE INVENTION

It is an object of the present invention to make a Miniature VeinEnhancer that is cost effective to manufacture.

It is another object of the present invention to make a Miniature VeinEnhancer that will allow a practitioner pinpoint a vein for intravenousdrip, blood tests, and the like.

It is still another object of the present invention to make a MiniatureVein Enhancer that will reduce and/or diminish the amount of botchedattempts to pierce a vein.

It is still a further object of the present invention to make aMiniature Vein Enhancer that is easy to operate.

It is another object of the present invention to make a Miniature VeinEnhancer that may be disposed of after use.

It is yet another object of the present invention to make a MiniatureVein Enhancer that may be hand held.

It is still another object of the invention to make a Miniature VeinEnhancer that implements a Miniature Projection Head in Alternatingframe mode.

It is yet another object of the present invention to make a MiniatureVein Enhancer that implements a Miniature Projection Head that operatesin. Dual Buffer Mode.

It is yet another object of the present invention to make a MiniatureVein

Enhancer that implements a Miniature Projection Head that operates inReal Time Mode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the Vein Enhancer of the presentinvention.

FIG. 2 is a perspective view of a prior art scanning laser based camera(SLBC) that implements a MEMS scanner with three photoreceptors.

FIG. 3 is a perspective view of the Vein Enhancer of the presentinvention with a MEMS scanner that implements two photodiodes.

FIG. 4 is a functional block diagram that illustrates the presentinvention operating in Alternating Frame Mode (AFM).

FIG. 5 is a functional block diagram that illustrates the presentinvention operating in Dual Buffer Mode (DBM).

FIG. 6 is a functional block diagram that illustrates the presentinvention operating in Real-Time Mode (RTM).

FIG. 7 is a functional block diagram that illustrates the interfacesbetween different components of the present invention.

FIG. 8 is a perspective view of the present invention with a polarizingfilter and an infrared filter placed in front of the photodiode.

DETAILED DESCRIPTION OF THE INVENTION

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention, which may be embodied in variousforms. Therefore, specific structural and functional details disclosedherein are not to be interpreted as limiting, but merely as a basis forthe claims and as a representative basis for teaching one skilled in theart to variously employ the present invention in virtually anyappropriately detailed structure.

A detailed description of the different configurations of lasers,mirrors, diodes, gain control systems, as well as the different powercontrols located inside the MPH will now be discussed. A detaileddescription of the MPH will then follow.

The present invention can be arranged as either a binary system orgrayscale system. In a grayscale system, the 740 nm signal received bythe PD is simply echoed and re-transmitted by the visible 638 nm laser201. In this manner, various levels of intensity can be shown.Accordingly, the image of a vein may vary in intensity as a function ofthe magnitude of signal received. In a binary system, the projectedimage is either on or off. To determine whether the projected imageshould be on or off, a comparator with a trip point is placed after thephotodiode. If the signal crosses the trip point the output laser 638 nm201 is turned on and vice versa. There are several ways to set the trippoint. For example, a user dial or press button (or any other inputmeans) could be placed on the device, and the user can manually adjustthe trip point (essentially making the device more or less sensitive).

The vein enhancer of the present invention, implements at least twolasers, 201 and 202, contained in the same housing, as seen in FIG. 1,which makes for easier operability and maintainability, that is, lesschance of losing one of the devices, as in citied prior art. Inaddition, the present invention has: improved beam combiner glass,higher power IR, improved mirrors, smaller photo diode setup; used forcollection optics, cables for electronic hook-up, AGC, and amicroprocessor; used for mirror control and laser calibration. With allthe aforementioned enhancements many significant improvements in thevein enhancement art can be obtained, one area in particular, is safety.

Laser projection devices have agency regulations dictating power outputlimitations. Generally, the power of a laser is limited to a thresholdlevel so as to protect the user's eye from injury. If, however, theuser's eye is prevented from getting too close to the laser, then thepower of the laser may be increased. Prior art in the past haveimplemented physical barriers that are incorporated into the design ofthe laser. These barriers help prevent the user's eye from getting tooclose to the origin of the laser projections, thus laser power may beincreased. For example, previous prior art have used protruding bars(similar to those used in football helmets) that are placed in thedirection of the optical path. This prevents the user from placing aneye too close to the laser.

In the present invention, signal processing can be utilized to controlthe power output. For example, in one embodiment the acquired imagepattern is stored in a computer memory. The image is then processed todetermine whether veins are present, and only upon confirmation of thevein being present is the image projected. In this manner, the visiblelaser will not be turned on if the laser is in the direction of theuser.

In another embodiment, the power of the 740 nm laser 202 can be set toan initially low setting. Once the laser detects a vein, the power ofthe 740 nm laser 202 can be increased and the 638 nm laser 201 turnedon.

In yet another embodiment, the laser can be configured so that the laserwill only be activated when a proximity sensor 220 determines thesurface, or eye of a user. The interface of proximity sensor 220 and themain electronics 260 may be seen in FIG. 7.

Although the vein enhancer of the present invention may be configured tooperate in a multitude of ways, it includes at least one laser, onephoto diode and at least one mirror. Depending on the desired outputand/or operating costs additional components may be incorporated intothe design of the present invention. Two embodiments that have beenfound useful in the vein enhancement art will now be discussed, adiscussion of alternative embodiments will follow.

Both embodiments implement 2 photo diodes (hereinafter PDs) and at leasttwo lasers. In addition, depending on the desired result, there can be apolarization film 270, as seen in FIG. 8, placed on the PD, thus furtherreducing specular reflection. This works particularly well withembodiments of the present invention which include a 740 nm laser and abroad spectrum PD.

Regarding the first embodiment, it is necessary to co-axially align thetwo lasers. Co-axially aligning the two lasers can be achieved in amultitude of ways. Two methods that have proven to be effective includeimplementing, either, a dielectric mirror or a polarizer.

The first configuration includes a first laser calibrated to transmitlight in the Infrared (hereinafter IF) spectrum, that is 740 nm, and asecond laser calibrated to transmit a light in the red color spectrum,that is ≈638 nm. The first configuration, as mentioned above, implementsa hot mirror 204 coated with a Dichroic substance, which separates anddirects the light onto two separate diodes. This system allows thevisible and IR laser reflections in real-time without the use of amemory chip. With this embodiment the 638 nm laser 201 is orientedbehind the dielectric mirror. The dielectric mirror is selected so thatthe 638 nm laser light passed through but the 740 nm is reflected. The740 nm laser is aimed at the front of the dielectric mirror and isangled and aimed so that the refection of the 740 nm laser is coaxialwith the 638 nm laser passing through the dielectric.

In the second configuration, the 638 nm laser is polarized in a firstorientation and is placed behind the polarized element. The polarizedelement is selected so that the first polarized orientation passesthrough, but the second polarized angle is reflected. The 740 nm ispolarized to the second polarized angle and is aimed at the front of thepolarized element and is angled and aimed so that the reflection of the740 nm laser is coaxial with the 638 nm laser passing through thepolarized element.

Regarding the second embodiment, the two lasers are multiplexed. It hasbeen noted that the signal received by the 740 nm PD of the presentinvention is representative of both the veins and the surface topologyof the patient. Put another way, the surface of the patient affects thereflected signal. This is not desirable, in that the area of interest isthe veins of the patient and not the surface topology of the patient.Thus, by using a second PH for receiving the 630 nm reflected signal,the 630 nm signal (the topology) can be subtracted from the 740 nmsignal (topology+veins) yielding a signal that is solely the veins(topology+veins−topology=veins). In this system the microprocessor 250or state machine circuit, as seen in FIG. 8, can record the reflectionfrom the visible laser and the IR laser can be turned on for one frame,every other frame, or every other scan line. Hence, a new signal wouldcontain a combined laser reflection. The new signal would then besubtracted from the visible signal only, thus leaving the IF signal. Theadvantage here is that the visible laser does not have to be turned off,which has the benefit of not attenuating the visible light while readingthe IF laser reflection.

Other configurations may include a Multi laser array and a LED. First,the Multi laser array will be discussed. In this embodiment a lineararray of visible lasers and. a linear array of IR lasers may replace thesingle visible laser and single IR laser. With this type ofconfiguration, the linear array of visible lasers and linear array of IRlasers are reflected off a single mirror that oscillates. An advantageof this laser configuration is twofold. First, the mirrors beingimplemented are less complex. Second, the collection means of thereflected IR light can be obtained by a retro collective mirror. A retrocollective mirror is a mirror that has a field of view that correspondsto the array of lasers and moves in concert with the movement of thearray of lasers. A characteristic that makes the retro collective mirrorideal for this configuration is the improved signal to noise ratio(SNR).

Evident from the above disclosure, it may be desired to implement one PD207, as can be seen in FIGS. 1 and 8. In the embodiments that implementone PD, that PD is usually responsive to the 740 nm wavelength but notthe 638 nm wavelength. In this manner both lasers can be on at the sametime without having the 638 laser couple into the PD. However, the sameresults can also be achieved via opposite modulation.

In another embodiment the, 638 nm and 740 nm, lasers may be modulatedoppositely. In this embodiment the PD will also be responsive to the,638 nm and 740 nm, laser, but the lasers will be modulated in oppositedirections. More specifically, both the lasers can be pulsed on and offat high rates without affecting the apparent quality of the image (638nm projection), or the quality of the acquired image (the reflections ofthe 740 nm laser). By synchronizing the two lasers so that themodulation is in opposite directions (the 638 nm on and 740 nm off,followed by, 638 nm off and 740 nm on), the image acquisition circuits(PD and amplifiers, if implemented) can be arranged to ignore signalswhen the 638 nm laser is on. In this embodiment, the visible 638 nmlaser does not interfere at all with the image acquisition apparatus.

All the aforementioned embodiments implemented either single or multiplelasers. It shall be disclosed now that in all aforementioned embodimentsa tightly focused LED may replace the lasers. It should be mentionedthat this embodiment has limited use in that the resulting projectionwill not be a collimated laser beam and it will diverge over distance.However, in those limited instances where the distance from the deviceto the surface is closely held, an appropriate focusing can be obtained.

The present invention also includes a means for gain control. Twopossible methods of adjusting the gain of the system are possible. Aprior art method of adjusting gain is to fix the 740 nm laser output andto adjust the gain of the photo detection circuitry so as to get anappropriate signal (not too low and not saturated). However, there iscomplexity in such an adjustment due to the speed requirements of thephoto detector gain adjustment. An alternative approach, as in thepresent invention, is to fix the gain of the photo detection circuitry,as in prior art, but adjust the power output of the 740 nm laser so thatan appropriate signal is outputted from the photo detection circuitry(once again not too low, but not saturated). It is much easier to designcircuits that adjust the 740 nm lasers due to the extremely highmodulation bandwidth of the lasers. For example, the 740 nm laser may bemodulated as needed to prevent saturation of the photo detectorcircuitry. Alternatively, the amplitude of the 740 nm laser can beadjusted to provide appropriate signal out of the photo detectioncircuitry.

Throughout all the embodiments previously discussed, adjusting the powerof either the 638 nm laser, or 740 nm laser, can be achieved by eitheradjusting the current to the lasers, or alternatively, modulating thelasers on and off at a rapid rate. Regarding modulation, depending uponthe duty cycle (pulse-width-modulation), the average laser intensitywill be changed. With respect to the visible 638 nm laser, the human eyewill integrate the signal and, provided the frequency of the PWM isfaster than the eye integration time, the laser will appear dimmer asthe on cycle time decreases, and vice versa. The power of the 740 nmlaser may be also be adjusted by PWM, this modulation will have the sameeffect upon the received signal as if the current was decreased to thelaser.

The MPH will now be described. FIG. 2 shows a prior art scanninglaser-based camera (hereinafter SLBC) 170 of Microvision, Inc. FIG. 17is taken from Microvision's website:(http://www.microvision.com/technology/imaging_works.html) dated Jan. 7,2006, herein incorporated by reference. The SLBC 170 includes a lasersource 171 which gets reflected off mirror 172 to a MEMS scanner 173.The MEMS scanner 173 has a reflective surface that can be oscillated inboth the X and Y axis. The oscillation of the MEMS scanner 173 iscontrolled by electronics (not shown) so that the reflected laser beamis moved in a raster pattern. To create a color camera, the laser sourceis a combination of a red, green and blue laser, thereby forming thecolor white. Three photodetectors, one responsive to red 175R, oneresponsive to blue 175B, and one responsive to green 175G are positionedon the SLBC 170 and receive the rastered laser light reflected offobject 176. The output of the photodetectors 175R, 175B, and 175Bprovide an analog rastered image representative of the object 176. Theoutputs of the photodetectors are converted from an analog signal to adigital signal by D/A converters (not shown). A controller (not shown)determines the instantaneous rastered laser light position and convertsthat to an appropriate pixel location. The controller then writes thedigitized RGB values to an appropriate pixel memory location. Byrepeating this step for each pixel location, a digitized version of theobject is stored in memory. Each raster sweep of the field of view 4results in a new image being stored. By sweeping at video rates, videoimages can be captured.

A publication in Laser Focus World, December 2004, authored by ChrisWiklof. entitled “Display technology spawns laser camera”, hereinincorporated by reference, describes the SLBC of FIG. 2 in even greaterdetail.

Drawing one's attention to FIGS. 4-6 are three different modes ofoperation that the present invention may be used, a brief description ofeach mode of operation follows.

A first mode of operation which will be referred to hereinafter as an“Alternating Frame Mode” (AFM) may be seen in FIG. 4. In the AFM mode,an electronic block 192 for driving the MEMS driver and for sensing theposition of the raster scanner is provided 192. This block generates thesignals required to drive the MEMS scanner 173 in a raster pattern, andalso determines the exact instantaneous location of the MEMS scanner andcommunicates this information to an image memory 191. This electronicblock 192 also generates output signals and indicates whether thecurrent frame (a frame is a complete raster of the field of view) is anodd number Frame 1 or an even number Frame 2 (essentially the twosignals are opposite and switch polarity every other frame). Theoperation is as follows. The MEMS 173 is driven in a raster pattern. Thefirst full frame after achieving a stable raster pattern will beidentified as an odd number frame and the laser driver 195 for the 740nm laser 183 is turned on for the entire frame. During this time thelaser drive 194 for the 630 nm laser is turned off. The light from the740 nm is absorbed by the veins in a patient's body and reflected by theskin of the patient, thus forming a contrasted image that is then sensedand converted into an analog signal by 740 nm photodetector 182. Theanalog signal is then passed through an A/D converter 190 which outputsa digital representation to image memory 191. Image memory 191 alsoreceives instantaneous position information from the electronic block192, and based upon such information, the digital representation isstored in a memory location corresponding to a particular pixel. This isrepeated for each pixel within the odd frame. Upon completion of the oddframe, the image memory contains the image of the veins within the fieldof view of the MPH. During the even number frame, the laser driver 195to the 740 nm laser is turned off. The data in the image memory 191 isread out as a function of the instantaneous position information provideby the electronic block 192 and provide to a D/A converter 193 whichoutputs an analog signal to laser drive 194 which drives the 630 nmlaser. In this manner, the image that was stored in the odd number frameis projected by the 630 nm laser 180 in the even number frame. In thismanner, the veins that are in the field of view become visible to thepractitioner.

A second mode of operation is shown in FIG. 5. This mode shall bereferred to hereinafter as the “Dual Buffer Mode” (DBM). In the DBM, asecond image memory called image memory two 196 is added. In the DBM,the laser driver to the 740 nm laser is turned on for every frame and ineach frame the image of the veins is captured and stored in image memory191 exactly as described previously in the AFM mode. However, in thiscase the electronic block 192 provides an end of frame indication toboth image memory two 196 and image memory 191 which causes the entireimage stored in the image memory 191 to be transferred to image memorytwo 196 during the blanking time of the raster scan (the time after theraster scan is completed but before the next raster scan starts). Duringthe next frame, the contents of image memory two 196 is then projectedby the 630 nm laser onto the field of view. In this manner, the visibleimage projected is always on frame behind the actual image captured.Provided the frame rate is fast enough, this delay should not beapparent to the practitioner. Frame rates in excess of 30 frames persecond can easily be achieved with the MEMS scanner provided herein.

The DBM mode is advantaged as compared to the AFM in that the visiblelaser is on every frame, and therefore is twice as bright. However, theAFM mode is advantaged in that it only requires a single memory bufferand therefore is more cost effective than the DBM mode.

A third mode of operation is illustrated in FIG. 6. This mode shall bereferred to hereinafter as the “Real Time Mode” (RTM). In the RTM theMEMS 173 is driven in a raster pattern by a MEMS driver 210. The laserdriver 195 to the 740 nm laser is turned on all the time. The reflectedlight is received by the 740 nm photodetector 182 and the analog signalproduced is connected to the laser driver 194 for the 630 nm laser 180.In this manner the red laser 180 projects nearly instantaneously thesignal that is being received by the photodetector 182. The only delayis dictated by the speed of the photodetector and the laser drive 194circuitry. Accordingly, there is no need for an image memory buffer andassociated D/A converters and A/D converters. Further, since the imageis never stored, there is no requirement to sense the instantaneousposition of the laser for the purpose of clocking the image into memoryor for projecting the visible image. In fact, in this RTM, the rasterpattern does not need to be as steady and repeatable as that of theother modes, thereby possibly decreasing the complexity and cost of theMEMS and associated drive circuitry.

Drawing one's attention now to FIG. 1 is a preferred embodiment 200 of aMPH the present invention. This embodiment replaces the MEMS scannerwith a two dimensional mirror. One such two dimensional mirror isprovided by Fraunhofer IPMS. In a press release dated Jan. 3, 2005 theydescribed a two dimensional mirror as follows:

-   -   “Projection devices based on laser scanning are a very        interesting alternative to matrix displays. A modulated laser        and a deflection unit are necessary. Using micro scanning        mirrors for implementing the laser beam deflection in a        projection device has many advantages. In particular, micro        scanning mirrors, which operate resonantly in both directions,        enable the development of systems with very small size, high        deflection angles with low voltage and low power consumption.        The presented demonstrator uses a commercial laser module and a        2D micro scanning mirror operated with deflection frequencies of        9.4 kHz and 1.4 kHz. The device uses both axes to perform a        sinusoidal oscillation, which causes a beam trajectory that        describes a Lissajous pattern with high density, instead of the        usually implemented linear scanning. Therefore, mirrors with low        ratio of horizontal and vertical deflection frequency can be        used. This kind of micro scanning mirrors can be fabricated        easily and cost effective. The control circuit is developed with        an FPGA and provides a resolution of 256.times.256 monochromatic        pixels. Programmable counters are used for generating the mirror        driving signals and for determining the beam position. Mirror        excitation and image synchronization work without feedback loop.        This means, no complicated optical or electronic synchronization        techniques are needed. This simplifies micro scanning mirror and        control circuit and enables low cost production. Applications of        the projection device are displays, laser marking and laser        exposure.”In the RTM of FIG. 6, the two-dimensional mirror of        Fraunhofer IPMS creates a Lissajous pattern with high density        instead of the raster pattern. The visible laser will simply        follow nearly instantaneously the image detected by the 740 nm        laser detector.

The MPH 200 may also include two laser sources. A first laser source 201having a wavelength in the visible light spectrum, preferably 632 nm,and a second laser 202 having a wavelength preferably 740 nm, that isIR. Lasers 201 and 202 may be any suitable lasers known in the art.

Combiner 203 may have at least one bounce mirror. In a preferredembodiment there can be two bounce mirrors, 203 a and 203 b. In thepreferred embodiment combiner 203 may also include a dielectric coatedmirror 204. Mirror 204 may be any suitable type of dielectric coatedmirror known in the available art. In a preferred embodiment mirror 204was coated with a material that reflects IR and transmits otherwavelengths. As mentioned above, the embodiment as depicted in FIG. 1replaces the MEMS scanner with a two dimensional scanning mirror 205,such as the type provided by Fraunhofer IPMS. With this embodiment therecan also be a collection mirror 206, and at least one PD 207.

In normal operation, the embodiment as depicted in FIG. 1 operates aspreviously discussed, that is, in any of the three operating modes;however, it performs optimally in RTM. In yet another embodiment thelasers can be multiplexed, in which case the visible laser would nothave to be turned off. In this embodiment all components would functionin a similar manner as previously mentioned embodiments. However, themicroprocessor or state machine 250 in this embodiment, as seen in FIG.7, can record the reflection of the visible laser 201 and then the IRlaser 202 can be turned on for any interval time duration, and combinedwith the visible laser. Thus, the resultant beam 240 would be acombination of both lasers. Beam 240 would be then subtracted from thepreviously recorded visible laser. The advantage here is that theprojected visible laser would not be reduced by turning off the visiblelaser to read the infrared laser reflection.

In another embodiment of the present invention there can be what isknown in the art as a “hot mirror”. Mirror 206 is preferably coated witha dichroic coating. This acts as a beam splitter. In normal operationmirror 206 will direct the light onto two separate PDs. With this typeof embodiment all other previously mentioned components may operate inthe same manner. In normal operation laser 202 will transmit IR light220 which will bounce off of bounce mirror 203 a. At which time laser202 will begin to transmit light 221 at 632 nm. Light 221 will passthrough dielectric coated mirror 204 and light 220 will reflect ofmirror 204, resulting in a beam of light 222 that is a combination ofboth lights, as seen in FIG. 1. Beam 222 will then be reflected ofbounce mirror 203 b. The angle at which beam 222 is reflected willdepend on the angle at which bounce mirror 203 b is placed. This will bedetermined by the manufacturer's design requirements. Once reflected offbounce mirror 203 b beam 222 will be projected onto the area ofinterest, that is, the area where the vein is located, via twodimensional scanning-mirrors 205. The projected beam 222 will then becollected by collection mirror 206. After which, collected beam willthen be passed through hot mirror 206 to separate and direct beam 222onto two PDs 207. This embodiment compares the visible light and the IRlaser reflections in real-time, without a memory chip.

Other embodiments may implement a MEMS scanner, as seen in FIG. 3, toperform the same function as the two dimensional mirrors. This willdepend on economic as well as practicable considerations.

Furthermore, there can be any array of polarizing filters and/orinfrared filters located between the collection mirror and thephotodiode, as seen in FIG. 8.

In the embodiments herein the visible light transmitted was a red laser.However, any visible color or combination of color could be transmitted.For example, three laser RGB could be utilized to transmit full colorimages onto the field of view.

While in the embodiments herein a single two-dimensional mirror whichmoves in two axis was used for steering the beam, other beam steeringarrangements could be used. For example, the outgoing laser beams can bebounced first off a one dimensional high speed scanning mirror and thenoff a second lower speed mirror scanning in the opposite direction.There are many other methods known to those skilled in the art forcreating raster and other scanned laser patterns.

While many of the embodiments described herein utilized vial holderswith needles, there are many other medical procedures which need to viewthe veins. The invention is not intended to be limited to devices whichattach to vial holders.

As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description shall be interpreted asillustrative and not in a limiting sense. In the view above it will beseen that several objects of the invention are achieved and otheradvantageous results attained, as defined by the scope of the followingclaims.

What is claimed is:
 1. A vein imager configured to image subcutaneousveins of a target area on a patient, said vein imager comprising: aminiature projection head, said miniature projection head comprising:means for imaging subcutaneous veins of the target area and forprojecting said imaged subcutaneous veins onto the target area at afirst intensity level and alternatively at a second intensity level,said second level being higher than said first level; said miniatureprojection head comprising a housing configured to receive said meansfor imaging and projecting therein; said housing comprising: an openingconfigured to provide an optical path for said imaging and projecting; aproximity sensor, said proximity sensor configured to detect the targetsurface when within a threshold distance away from said vein imager; andwherein said means for imaging and projecting is configured for saidprojecting normally being at said first intensity level; and whereinsaid means for imaging and projecting is configured for said projectingbeing at least at said second intensity level, when said proximitysensor detects the target surface.
 2. The vein imager according to claim1, further comprising: a computer memory, said computer memoryconfigured to receive and store said imaging from said means for imagingand projecting; means for signal processing for determining whensubcutaneous veins are present in said stored imaging; and wherein saidmeans for imaging and projecting is further configured for saidprojecting only when veins are present in said stored imaging.
 3. Thevein imager according to claim 2, further comprising: a comparator withan adjustable trip point; wherein said means for signal processing isfurther configured for determining an intensity of the vein when veinspresent in said vein imaging; and wherein said comparator compares saiddetermined intensity of the veins to said trip point, and saidprojecting only occurs when said determined intensity is above saidadjustable trip point.
 4. The vein imager according to claim 3, furthercomprising a dial; and wherein said adjustable trip point of saidcomparator is adjusted using said dial.
 5. The vein imager according toclaim 3, further comprising: a microprocessor; and means for receiving areflected signal representative of a surface topology of the targetarea; wherein said means for imaging and projecting is furtherconfigured for multiplexing of said imaging and said projecting, eachbeing in every other frame; and wherein said microprocessor is furtherconfigured for removing said reflected surface signal of the target areafrom a next frame of said projecting using said received signalrepresentative of surface topology of the target area within a currentframe of said imaging.
 6. The vein imager according to claim 5, furthercomprising means for controlling gain, for preventing saturation.
 7. Thevein imager according to claim 6, further comprising: means ofsupporting said miniature projection head permitting single-handedlifting and use of said vein imager during handheld imaging of thetarget area in a venipuncture procedure.
 8. The vein imager according toclaim 7 wherein means for imaging and projecting uses a wavelength inthe range of 700 nm to 1000 nm for said imaging, and a visible redwavelength of light for said projecting.
 9. The vein imager according toclaim 6, wherein said housing comprises: a hand-holdable housingconfigured to permit single-handed lifting and use of said vein imagerduring said handheld imaging of the target area in a venipunctureprocedure.
 10. The vein imager according to claim 9, further comprisinga cap; and wherein said hand-holdable housing comprises a holderconfigured to receive a battery; said cap configured to be releasablysecured to said housing to provide access to said battery holder. 11.The vein imager according to claim 10 wherein means for imaging andprojecting uses a wavelength in the range of 700 nm to 1000 nm for saidimaging, and a visible red wavelength of light for said projecting. 12.A vein imager configured to image subcutaneous veins of a target area ona patient, said vein imager comprising: a miniature projection head,said miniature projection head comprising: means for imagingsubcutaneous veins of the target area and for projecting said imagedsubcutaneous veins onto the target area at a first intensity level andalternatively at a second intensity level, said second level beinghigher than said first level; said miniature projection head comprisinga housing configured to receive said means for imaging and projectingtherein; said housing comprising: an opening configured to provide anoptical path for said imaging and projecting; means of supporting saidminiature projection head and permitting single-handed lifting and useof said vein imager during handheld imaging of the target area in avenipuncture procedure. means for detecting the target surface whenwithin a threshold distance away from said vein imager; and wherein saidmeans for imaging and projecting is configured for said projectingnormally being at said first intensity level; and wherein said means forimaging and projecting is configured for said projecting being at leastat said second intensity level, when said means for detecting detectsthe target surface.